The OP said he started the bike with the truck, and that it was hooked up a while during starting, and presumably for a few minutes while running. He then rode it quite a bit during the next few days.
Here is a possible scenario:
Motorcycle stators produce 100% of their power, all of the time. Whatever the bike doesn't use for its various systems is shunted to the regulator which disposes of the excess as heat. So far so good because the bike has limited power available and the regulator can cope with the balance. Effectively, it is a balanced system that is set up so the bike plu the regulator demand full power, and the stator supplies it.
Enter a truck with an alternator capable of producing 1000W, but only actually producing what is demanded at any one time.
The truck alternator sees the regulator on the bike as a power-demanding beast, and ramps up its output to supply what is asked. This could be several hundred watts of power which the bike doesn't really want, but Mr Alternator cannot know this and diligently fries the regulator on the bike. This is a well-trodden path and the reason bikers are advised NOT to jump start a bike from a running car.
Now we have a running bike with a damaged regulator. The regulator has two jobs to do. It regulates the output to 14.5V or so, and absorbs the excess current. If it cannot do this then it is quite possible the bike is getting unregulated DC voltage much higher than the battery can handle, and for several hours. There are usually several symptoms, one of which is a very hot battery. Others include super-bright, or blown lightbulbs.
Alternator and stator systems are electrically incompatible and when you connect them, both running, the bike suffers.
I'm not saying this is what happened, but the OP indicates that this could very easily have happened and there is an easy test. Hook up the new battery, start the bike and check the voltage.
